var fontSize = !(function(doc, win) {
  var docEl = doc.documentElement
  var resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize'

  var recalc = function() {
    var clientWidth = docEl.clientWidth
    if (!clientWidth) return
    docEl.style.fontSize = '100px'
    if (200 * (clientWidth / 750) <= 1000) {
      docEl.style.fontSize = 200 * (clientWidth / 750) + 'px'
    }
  }
  recalc()
  if (!doc.addEventListener) return

  win.addEventListener(resizeEvt, recalc, false)
  doc.addEventListener('DOMContentLoaded', recalc, false)
})(document, window)
